The present invention relates to saturated fluid mixtures and their generation, which saturated fluid mixtures are useful as an environment in the melting, heat treating, welding, cold-treating, casting, surface treating, and the like of metallic and non-metallic materials by which desired properties in the materials are obtained.
It has long been desired in the art to produce a furnace atmosphere that is in equilibrium, that is, one that would be "neutral" to metallic or non-metallic bodies at any given temperature. For example, in the heat treating of steel the problem of scaling, decarburizing and carburizing is always present in the higher temperature ranges and discoloration, scaling, decarburizing and the like is always present in the lower temperature ranges. Prior to the present development, there were no energy balanced saturated fluid mixtures in use in the metallurgical art, or generators or methods for generating such mixtures. Furnace atmospheres were generated and controlled through chemical means rather than by the thermodynamic means of this invention. The prior environments were generated containing high percentages of carbon monoxide, which is a carburizing constituent, and high percentages of hydrogen which is a decarburizing constituent. The chemical control of the environment consisted of making the carburizing tendency approximately equal to the decarburizing tendency, thus providing environments of the state of the art before the present invention. This has not been entirely satisfactory. For example, one difficulty is that the rates at which the carburizing and decarburizing reaction takes place change with a change of furnace temperature which results in either a carburized or decarburized condition.
Also, in the metallurgical art before the present development, there was no furnace atmosphere for treating metals and non-metals which by simply controlling temperature and pressure of the atmosphere during its generation and transportation to the treating zone is neutral, oxidizing and decarburizing, oxidizing and carburizing, reducing and carburizing or reducing and decarburizing so that desired properties can be imparted to these metals and non-metals.
The present invention is directed to such saturated fluid mixtures and to methods of producing them.